How Serious is Testicular Cancer in Dogs?

Testicular cancer in dogs is common in intact male dogs. However, there are some intact dogs who may go on to develop testicular cancer. That’s not an excuse not to have your dog neutered, however.

Other factors for testicular cancer in dogs include things like environmental contaminants, age, and genetics. The best overall way to drastically lessen the chance of your dog developing testicular cancer is to have him castrated by a licensed veterinarian.

Dog Breeds at Higher Risk of Testicular Cancer

Any male dog 10 years of age or over is more prone to testicular cancer. However, there are some breeds in particular that seem to be predisposed. The breeds include:

German Shepherds


Afghan Hounds


Shetland Sheepdogs



The risks are even higher with dogs that have undescended testicles. In a case where your dog has one testicle that is not descended, there is a high risk of developing testicular cancer in this one testicle.

Symptoms of Testicular Cancer in Dogs

Most of you will never be able to tell whether your dog has testicular cancer or not. Most testicular cancers in dogs are found through a physical examination by a licensed veterinarian or technician. While palpating organs and the testicles, the veterinarian may discover a lump or small mass in the area.

The best advice is to look for testicular swelling, enlarged mammary glands, and fur loss. Having an intact dog regularly checked by a veterinarian is the best way to catch disease early. Luckily, testicular cancer in dogs usually stays within that area and doesn’t easily metastasize.

Generally speaking, there are a variety of symptoms to watch for that could suggest cancer in dogs. It’s not to say that any or all of these symptoms mean your dog has cancer. Oftentimes, there are other conditions at play that are not life threatening. Nevertheless, it’s best to pay attention and seek veterinarian advice for the following:

Lumps and bumps

Skin lesions

Coughing, sneezing, vomiting, or diarrhea (with or without blood)

Seizures (late onset)

Unexplained weight loss

Abdominal distention

Enlarged lymph nodes

Mammary tumors

Vaginal discharge

Testicular irregularities

3 Main Types of Testicular Cancer in Dogs

There are 3 main types of testicular cancer in dogs that you should be aware of. These include:

Sertoli Cell Tumors

This type of testicular cancer is the most common in dogs. These will appear as a swelling in the testicles or the scrotum area.

The size of the affected testis is usually two to three times larger than those in healthy dogs. Among differential diagnosis of testicular enlargement or feminization syndrome, ICT, SCT and seminomas are prime considerations. 

Bigliardi, E, Denti, L, De Cesaris, V, et al. Colour Doppler ultrasound imaging of blood flows variations in neoplastic and non‐neoplastic testicular lesions in dogs. Reprod Dom Anim. 2019; 54: 63– 71.

Sertoli cells create estrogen which can lead to a condition known as “hypoestrogenism”. This condition causes enlarged mammary glands, enlarged prostate, anemia, or symmetrical hair loss. This process is likened to the feminization of a male dog and is easily noticeable.

In rare cases, the Sertoli cells may metastasize in the lungs, brains, abdomen or thymus.


Seminomas are the second most common testicular tumors found in dogs. They are very small and develop as a result of an undescended testicle. Breeds who develop seminomas are typically over the age of 4. These can be really hard to find on a dog and usually produce few, if any, symptoms.

If you’re very observant, however, you may notice that your dog shows some sign of pain (pulling away, flinching, vocalization) when the testicle is palpated. At less than 2 cm, these tumors are very hard to find. Luckily, it’s rare for these tumors to metastasize and spread to other organs.

Breeders, who don’t have their dogs castrated for obvious reasons, need to take particular care. It’s important to keep regularly scheduled appointments with a licensed veterinarian. A veterinarian who knows your dog will be able to tell what’s normal and what isn’t. Small changes can be detected by an experienced professional.

Interstitial Cell Tumors in Dogs

Interstitial cell tumors are benign (non cancerous) and are common in older dogs over the age of 10. All dog breeds (intact males) are susceptible, but there seems to be a higher occurrence in boxers.

Interstitial cell tumors in dogs are usually found through routine physical examination. In some cases, the owner may notice changes to the color, texture, or size of the involved testicle.

How Does Testicular Cancer Progress?

Seminomas and sertoli cells generally have a less than 15% chance of spreading and interstitial cells will not spread at all.

There’s a small possibility that testicular cancer in dogs is actually a symptom of another cancer. For example, urinary tract cancers or cancers of the reproductive system may spread and reach the testicles.

The vet will need to perform a rectal check,X rays, urinalysis as well as a blood test. If the dog is cryptorchid (has an undescended testicle), a CT scan or an abdominal ultrasound may be done to check of any other affected organs.

How is testicular cancer in dogs diagnosed?

Suspicion of testicular cancer in dogs starts with visual evidence. You or the veterinarian may notice swelling, a change of color or texture of the testicle. In addition, your veterinarian may be able to feel subtle changes that could indicate the presence of a tumor.

If there is any concern that your dog may have testicular cancer, the veterinarian will order a series of tests that could include the following:


A sonogram measures and transmits a visual representation of sound. The procedure, known as an abdominal ultrasound, can detect scrotal lesions and the abnormal or excessive presence of blood vessels. These findings may suggest the presence of a tumor.

Ultrasounds are painless and can help to identify retained or undescended testes in the groin or abdominal cavity. In addition, ultrasounds help to visual lymph nodes and assess distant metastasIs (cancer that has spread). In addition, ultrasound can help detect abnormalities of the prostate gland.

Gray‐scale ultrasonography in combination with colour and power Doppler imaging has been well accepted as an accurate technique for assessing scrotal lesions and vascularization of the testis

Bigliardi, E, Denti, L, De Cesaris, V, et al. Colour Doppler ultrasound imaging of blood flows variations in neoplastic and non‐neoplastic testicular lesions in dogs. Reprod Dom Anim. 2019; 54: 63– 71.

Physical Examination (Scrotal Palpation)

Depending on the size of the mass, this is usually the most common way that testicular cancer in dogs is diagnosed.

Rectal Palpation

Other tests might include rectal palpation to check for signs of lymph node enlargement, complete blood count to detect a decrease in white blood cells, and ultrasound.

Abdominal X-rays

Exploratory Surgery

This type of surgery would likely only be suggested if the veterinarian suspects the tumor has spread to the lymph nodes. Keep in mind that the chance of testicular cancer spreading is very low.

Sperm Analysis

This test might sound a little extreme, but the reality is that sperm abnormalities can result from testicular tumors.

Chest X-rays

A simple chest x-ray can help determine whether the cancer has spread.


A biopsy is the removal of a small piece of tissue for evaluation under a microscope. Normally, biopsies (or fine-needle aspiration) are only performed after the surgical removal of the testicle. When done before surgery, the procedure can result in permanent damage to the testicular tissue.

Biopsy is essential after surgery to determine whether the cancer has spread or is likely to spread.

Read Your e-Guide to Dog Spleen Tumors.

How to Treat Testicular Cancer in Dogs

The most successful way of treating tumors in the testicles is through castration. Surgically removing a cancerous testicle can stop the progression of the disease while removing it entirely.

In the rare instances where testicular cancer has spread to other parts of the body, chemotherapy is the recommended option.

The Price of Testicular Cancer Treatment

Since the treatment of testicular cancer in dogs is pretty straightforward, costs tend to range from $300 to $400 for diagnosis and under $1000 for actual treatment. There are always exceptions, however, especially in rare but complicated cases.

The cost of neutering your dog will range in price depending on location. The Humane Society or a low-cost vet will charge anywhere from $50 to $150. Price depends on how risky the procedure is (age of dog could be a factor) to the size of your dog.

Prognosis for Testicular Cancer in Dogs

The prognosis is quite good for dogs that develop testicular cancer. In the majority of instances, castration is highly successful thanks to the low rate of metastasis.

Can Testicular Cancer in Dogs be Prevented?

Something tells me you already know the answer to this. Of course, castration (spaying or neutering) is the best way to prevent testicular cancer in male dogs. Other benefits of this procedure including the reduction of roaming, scent marking, aggression, and other unwanted dog behaviours like “humping”.

If you have a healthy breeding dog on the other hand, make sure you castrate them when they are past breeding age.

For the Love of Dog

Keeping your dog healthy and happy is really easy these days. Pet insurance, CostCare, and other payment plans can help if you don’t have the money for regular checkups and diagnostic tests. Unless you plan to ethically breed your dog, castration is the best way to prevent cancer.

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